As progress is made on any application, new and different requirements will likely be added. Sometimes these requirements enhance the existing functionality of the application. At other times, these new requirements may conflict with the existing functionalities. When requirements conflict, it's important that issues are resolved so that the proper functionality can be built.

So, what are the changes in requirements you might expect to see? Changes often consist of alterations to a business rule, new features or enhancements, or modifications needed to resolve a bug or defect discovered in the system.

As time goes on, there will often be a need to modify an existing business rule. This may be in response to user feedback, clarification from the business, or a need discovered through use of the system. When the need for change is discovered, then the existing application will need to change. A comprehensive test suite will ensure that the rest of the system still operates as expected once the new changes are implemented. Start by modifying and/or creating new tests to cover the new desired functionality of the system.

There's a common saying in software development that software is never finished; it is merely abandoned. That is to say that an application will continue to grow and evolve through new development if it is to continue to be useful. If new features aren't being added, then it is likely that the project has simply been abandoned. If an application is to continue to be of use, then you can expect that new features will need to be implemented. Again, start with the tests and add new tests which will help guide your implementation of any and all new features.

When a bug is discovered and the root cause identified, then a change will need to be made to resolve the issue. In order to prevent this bug from appearing again in the future, a new test, or series of tests, should be written to cover any potential scenarios that would result in the erroneous behavior.

In this chapter, we will gain an understanding of:

• Changing requirements
• A new feature
• Dealing with defects
• Changes to Speaker Meet
• Premature optimization